1 files changed, 51 insertions, 31 deletions

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 4f0f8c2e58a5..b6bedc3ee95c 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -32,11 +32,12 @@ extern struct bus_type spi_bus_type;
  * @max_speed_hz: Maximum clock rate to be used with this chip
  *      (on this board); may be changed by the device's driver.
  *      The spi_transfer.speed_hz can override this for each transfer.
- * @chip-select: Chipselect, distinguishing chips handled by "master".
+ * @chip_select: Chipselect, distinguishing chips handled by @master.
  * @mode: The spi mode defines how data is clocked out and in.
  *      This may be changed by the device's driver.
- *      The "active low" default for chipselect mode can be overridden,
- *      as can the "MSB first" default for each word in a transfer.
+ *      The "active low" default for chipselect mode can be overridden
+ *      (by specifying SPI_CS_HIGH) as can the "MSB first" default for
+ *      each word in a transfer (by specifying SPI_LSB_FIRST).
  * @bits_per_word: Data transfers involve one or more words; word sizes
  *      like eight or 12 bits are common.  In-memory wordsizes are
  *      powers of two bytes (e.g. 20 bit samples use 32 bits).
@@ -48,14 +49,18 @@ extern struct bus_type spi_bus_type;
  * @controller_state: Controller's runtime state
  * @controller_data: Board-specific definitions for controller, such as
  *      FIFO initialization parameters; from board_info.controller_data
+ * @modalias: Name of the driver to use with this device, or an alias
+ *      for that name.  This appears in the sysfs "modalias" attribute
+ *      for driver coldplugging, and in uevents used for hotplugging
  *
- * An spi_device is used to interchange data between an SPI slave
+ * A @spi_device is used to interchange data between an SPI slave
  * (usually a discrete chip) and CPU memory.
  *
- * In "dev", the platform_data is used to hold information about this
+ * In @dev, the platform_data is used to hold information about this
  * device that's meaningful to the device's protocol driver, but not
  * to its controller.  One example might be an identifier for a chip
- * variant with slightly different functionality.
+ * variant with slightly different functionality; another might be
+ * information about how this particular board wires the chip's pins.
  */
 struct spi_device {
         struct device           dev;
@@ -77,13 +82,15 @@ struct spi_device {
         void                    *controller_data;
         const char              *modalias;
 
-        // likely need more hooks for more protocol options affecting how
-        // the controller talks to each chip, like:
-        //  - memory packing (12 bit samples into low bits, others zeroed)
-        //  - priority
-        //  - drop chipselect after each word
-        //  - chipselect delays
-        //  - ...
+        /*
+         * likely need more hooks for more protocol options affecting how
+         * the controller talks to each chip, like:
+         *  - memory packing (12 bit samples into low bits, others zeroed)
+         *  - priority
+         *  - drop chipselect after each word
+         *  - chipselect delays
+         *  - ...
+         */
 };
 
 static inline struct spi_device *to_spi_device(struct device *dev)
@@ -146,6 +153,11 @@ static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
 
 extern int spi_register_driver(struct spi_driver *sdrv);
 
+/**
+ * spi_unregister_driver - reverse effect of spi_register_driver
+ * @sdrv: the driver to unregister
+ * Context: can sleep
+ */
 static inline void spi_unregister_driver(struct spi_driver *sdrv)
 {
         if (sdrv)
@@ -165,18 +177,20 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  * @setup: updates the device mode and clocking records used by a
  *      device's SPI controller; protocol code may call this.  This
  *      must fail if an unrecognized or unsupported mode is requested.
+ *      It's always safe to call this unless transfers are pending on
+ *      the device whose settings are being modified.
  * @transfer: adds a message to the controller's transfer queue.
  * @cleanup: frees controller-specific state
  *
- * Each SPI master controller can communicate with one or more spi_device
+ * Each SPI master controller can communicate with one or more @spi_device
  * children.  These make a small bus, sharing MOSI, MISO and SCK signals
  * but not chip select signals.  Each device may be configured to use a
  * different clock rate, since those shared signals are ignored unless
  * the chip is selected.
  *
  * The driver for an SPI controller manages access to those devices through
- * a queue of spi_message transactions, copyin data between CPU memory and
- * an SPI slave device).  For each such message it queues, it calls the
+ * a queue of spi_message transactions, copying data between CPU memory and
+ * an SPI slave device.  For each such message it queues, it calls the
  * message's completion function when the transaction completes.
  */
 struct spi_master {
@@ -280,27 +294,27 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
  * struct spi_transfer - a read/write buffer pair
  * @tx_buf: data to be written (dma-safe memory), or NULL
  * @rx_buf: data to be read (dma-safe memory), or NULL
- * @tx_dma: DMA address of tx_buf, if spi_message.is_dma_mapped
- * @rx_dma: DMA address of rx_buf, if spi_message.is_dma_mapped
+ * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
+ * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
  * @len: size of rx and tx buffers (in bytes)
  * @speed_hz: Select a speed other then the device default for this
- *      transfer. If 0 the default (from spi_device) is used.
+ *      transfer. If 0 the default (from @spi_device) is used.
  * @bits_per_word: select a bits_per_word other then the device default
- *      for this transfer. If 0 the default (from spi_device) is used.
+ *      for this transfer. If 0 the default (from @spi_device) is used.
  * @cs_change: affects chipselect after this transfer completes
  * @delay_usecs: microseconds to delay after this transfer before
  *      (optionally) changing the chipselect status, then starting
- *      the next transfer or completing this spi_message.
- * @transfer_list: transfers are sequenced through spi_message.transfers
+ *      the next transfer or completing this @spi_message.
+ * @transfer_list: transfers are sequenced through @spi_message.transfers
  *
  * SPI transfers always write the same number of bytes as they read.
- * Protocol drivers should always provide rx_buf and/or tx_buf.
+ * Protocol drivers should always provide @rx_buf and/or @tx_buf.
  * In some cases, they may also want to provide DMA addresses for
  * the data being transferred; that may reduce overhead, when the
  * underlying driver uses dma.
  *
  * If the transmit buffer is null, zeroes will be shifted out
- * while filling rx_buf.  If the receive buffer is null, the data
+ * while filling @rx_buf.  If the receive buffer is null, the data
  * shifted in will be discarded.  Only "len" bytes shift out (or in).
  * It's an error to try to shift out a partial word.  (For example, by
  * shifting out three bytes with word size of sixteen or twenty bits;
@@ -309,7 +323,7 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
  * In-memory data values are always in native CPU byte order, translated
  * from the wire byte order (big-endian except with SPI_LSB_FIRST).  So
  * for example when bits_per_word is sixteen, buffers are 2N bytes long
- * and hold N sixteen bit words in CPU byte order.
+ * (@len = 2N) and hold N sixteen bit words in CPU byte order.
  *
  * When the word size of the SPI transfer is not a power-of-two multiple
  * of eight bits, those in-memory words include extra bits.  In-memory
@@ -318,7 +332,7 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
  *
  * All SPI transfers start with the relevant chipselect active.  Normally
  * it stays selected until after the last transfer in a message.  Drivers
- * can affect the chipselect signal using cs_change:
+ * can affect the chipselect signal using cs_change.
  *
  * (i) If the transfer isn't the last one in the message, this flag is
  * used to make the chipselect briefly go inactive in the middle of the
@@ -372,7 +386,7 @@ struct spi_transfer {
  * @queue: for use by whichever driver currently owns the message
  * @state: for use by whichever driver currently owns the message
  *
- * An spi_message is used to execute an atomic sequence of data transfers,
+ * A @spi_message is used to execute an atomic sequence of data transfers,
  * each represented by a struct spi_transfer.  The sequence is "atomic"
  * in the sense that no other spi_message may use that SPI bus until that
  * sequence completes.  On some systems, many such sequences can execute as
@@ -464,8 +478,9 @@ static inline void spi_message_free(struct spi_message *m)
 }
 
 /**
- * spi_setup -- setup SPI mode and clock rate
+ * spi_setup - setup SPI mode and clock rate
  * @spi: the device whose settings are being modified
+ * Context: can sleep
  *
  * SPI protocol drivers may need to update the transfer mode if the
  * device doesn't work with the mode 0 default.  They may likewise need
@@ -474,7 +489,7 @@ static inline void spi_message_free(struct spi_message *m)
  * The changes take effect the next time the device is selected and data
  * is transferred to or from it.
  *
- * Note that this call wil fail if the protocol driver specifies an option
+ * Note that this call will fail if the protocol driver specifies an option
  * that the underlying controller or its driver does not support.  For
  * example, not all hardware supports wire transfers using nine bit words,
  * LSB-first wire encoding, or active-high chipselects.
@@ -487,9 +502,10 @@ spi_setup(struct spi_device *spi)
 
 
 /**
- * spi_async -- asynchronous SPI transfer
+ * spi_async - asynchronous SPI transfer
  * @spi: device with which data will be exchanged
  * @message: describes the data transfers, including completion callback
+ * Context: any (irqs may be blocked, etc)
  *
  * This call may be used in_irq and other contexts which can't sleep,
  * as well as from task contexts which can sleep.
@@ -535,6 +551,7 @@ extern int spi_sync(struct spi_device *spi, struct spi_message *message);
  * @spi: device to which data will be written
  * @buf: data buffer
  * @len: data buffer size
+ * Context: can sleep
  *
  * This writes the buffer and returns zero or a negative error code.
  * Callable only from contexts that can sleep.
@@ -558,8 +575,9 @@ spi_write(struct spi_device *spi, const u8 *buf, size_t len)
  * @spi: device from which data will be read
  * @buf: data buffer
  * @len: data buffer size
+ * Context: can sleep
  *
- * This writes the buffer and returns zero or a negative error code.
+ * This reads the buffer and returns zero or a negative error code.
  * Callable only from contexts that can sleep.
  */
 static inline int
@@ -585,6 +603,7 @@ extern int spi_write_then_read(struct spi_device *spi,
  * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
  * @spi: device with which data will be exchanged
  * @cmd: command to be written before data is read back
+ * Context: can sleep
  *
  * This returns the (unsigned) eight bit number returned by the
  * device, or else a negative error code.  Callable only from
@@ -605,6 +624,7 @@ static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)
  * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
  * @spi: device with which data will be exchanged
  * @cmd: command to be written before data is read back
+ * Context: can sleep
  *
  * This returns the (unsigned) sixteen bit number returned by the
  * device, or else a negative error code.  Callable only from